1) Field of the Invention
This invention relates to an optical waveguide element, a three-dimensional optical waveguide circuit and an optical system.
2) Description of the Prior Art
In such an optical waveguide element and a laser gyroscope using a thin film optical waveguide, a multi-level crossing optical waveguide is not realized on the same surface of a substrate. The reason is because light goes straight.
Recently, with the development of multiplexing technique in optical communication and the increase of the necessity for monolithic optical integrated elements, various multi-level crossing technique in optical communication paths have been developed.
However, it has not been succeeded to make the multi-level crossing optical waveguide on the same surface of the substrate by a conventional circuit manufacturing technique.
In view of the above actual situation, it is an object of the present invention to provide an optical waveguide element in which minute optical communication paths can be formed, a three-dimensional optical waveguide circuit and an optical system using the optical waveguide element.
For achieving the object, an optical waveguide element of the present invention comprises arranged plural spherical bodies with diameters of not more than 100 xcexcm made of transparent uniform glass.
Moreover, an optical waveguide element of the present invention also comprises arranged plural columnar bodies with diameters of not more than 100 xcexcm made of transparent uniform glass which are arranged in an orthogonal direction to their central axes.
According to the present invention, since the optical waveguide element is composed of minute transparent glass spherical bodies or minute transparent glass columnar bodies, it can have a minute optical communication path with a given shape. Moreover, in a preferred embodiment of the optical waveguide element, the glass spherical bodies or the glass columnar bodies may be arranged in straight or in curve. Therefore, the optical communication path can be formed in straight or in curve with a given curvature.
Moreover, in another preferred embodiment of the optical waveguide element, the transparent glass spherical bodies or the transparent glass columnar bodies arranged in straight or in curve, which are one unit, may be stacked. Thereby, a multi-optical communication path, in which plural of the planer optical communication path as one unit composed of the glass bodies arranged in straight or in curve are stacked, can be formed.
Furthermore, a multi-level crossing three-dimensional optical waveguide can be fabricated by combining the above optical waveguide element of the present invention and a thin film optical waveguide element.
Then, an optical system having a minute optical communication path with a given shape can be fabricated by combining the above optical waveguide element and an external optical system.
Japanese Laid-open Publication Kokai Sho 59-26702 (JP A 59-26702) discloses that image is transmitted through a flexible cylinder with spherical lenses made of optical glass therein. However, this invention relates to the optical communication, not the image transmission.
That is, in the image transmission, the astigmatisms in glass spherical bodies must be considered. For transmitting an image without its reversion and deformation, each glass spherical body is required to have a diameter of not less than 1 mm. Moreover, since the image does not converge into the glass spherical bodies arranged in curve in the transmission direction, it can not be transmitted.
On the contrary, in the optical communication according to the present invention, as mentioned later, the glass spherical bodies or the glass columnar bodies are required to have diameters of not more than 100 xcexcm because of its communication mechanism. Then, because of the communication mechanism, the linear optical communication or the curved optical communication is realized.
In other word, the technique disclosed in JP A 59-26702 is similar to this invention in geometrical optics, but the above technique is quite different from this invention in the transmission principle.
Moreover, Japanese Laid-open Publication Kokai Hei 3-175402 (JPA 3-175402) discloses that a transparent material with higher refractive index than that of the material constituting a substrate is fill up in minute openings formed on a flat surface of a substrate to form transmission paths, and images are transmitted through the transmission paths. In this case, referring to the above argument, the disclosed technique is quite different from this invention. Even in the embodiments in the publication, each image is transmitted through only one minute opening embedded by the transparent material via a semi-spherical lens.
Japanese Laid-open Publication Kokai Sho 62-81607 (JP A 62-81607) also discloses a similar technique to this invention. This publication discloses that an optical communication path is composed of a clad portion and a core portion made of a material with higher refractive index than that of the clad portion, and thereby, light is transmitted through the core portion. Therefore, the disclosed technique is different from this invention in which light is transmitted through plural uniform glass spherical bodies or plural uniform glass columnar bodies in their diameter direction.
Moreover, Japanese Laid-open Publication Kokai Hei 10-235202 (JP A 235202) discloses that light is transmitted in single columnar body in its longitudinal direction, and thus, is different from this invention.